The present disclosure relates generally to electrostatographic reproduction machines, and more particularly, concerns such a machine including a cleaning and spots blade lubricating method and apparatus.
In a typical toner image reproduction machine, for example an electrostatographic printing process machine, an imaging region of a toner image bearing member such as a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is irradiated or exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charges thereon in the irradiated areas. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document.
After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. The toner particles are heated to permanently affix the powder image to the copy sheet. Residual toner particles remaining on the photoconductive surface following image transfer as above are then removed by a cleaning apparatus in order to prepare the surface for forming another toner image.
The foregoing generally describes a typical black and white electrostatographic printing machine. With the advent of multicolor electrophotography, it is desirable to use an image-on-image architecture that comprises a plurality of image forming stations. One example of the plural image forming station architecture utilizes an image-on-image (IOI) system in that the photoreceptive member is recharged, re-imaged and developed for each color separation. This charging, imaging, developing and recharging, re-imaging and developing, all followed by transfer to paper, is done in a single revolution of the photoreceptor in so-called single pass machines, while multi-pass architectures form each color separation with a single charge, image and develop, with separate transfer operations for each color. Again as above, residual toner particles remaining on the photoconductive surface following image transfer as above are then removed by a cleaning apparatus in order to prepare the surface for forming another toner image.
It has been found that image-on-image processes, for example, create very high toner densities on the photoconductive or photoconductive surface. In some machines using toner particles with toner additives in similar multi-color processes, the additional use of control patches, and engagements in component-disturbing activities such as recovery from paper jams, together create conditions that make cleaning or removal of residual toner particles from the imaging region as well as elsewhere very challenging for ordinary conventional cleaning apparatus. In addition, cleaning devices, for example, urethane rubber blades for cleaning the image forming or carrying surface after each use will tend to scratch and abrade the image forming surface where there is insufficient lubrication at the interface between the blade and the image forming surface. Thus it is well known that the image forming surface must be sufficiently lubricated because lack of sufficient lubrication to the edges of such blades may and usually results in scratching and abrasion of the image forming surface. Such scratches and abrasions could rise to a level where they become printable and hence detrimentally affect the image quality. The situation is made worse when such conditions are combined with demands for higher process speeds, as well as demands for higher print quality, longer component lives and higher machine reliability.
The following references disclose examples of existing surface cleaning and treating devices. U.S. Pat. No. 6,775,512 issued Aug. 10, 2004 and entitled “Dual electrostatic brush cleaner bias switching for multiple pass cleaning of high density toner inputs” discloses apparatus for removing charged particles from a surface, the surface being capable of movement, including: a preclean corotron having a first polarity; and a first cleaning brush for cleaning charged particles from the surface, having a second polarity different from the first polarity of the preclean corotron; a second cleaning brush for cleaning the charged particles from the surface, having a predefined polarity, the second cleaning brush being located downstream from the first cleaning brush, in the direction of motion of the surface; and a controller for changing the predefined polarity of the second cleaning brush from the first polarity to the second polarity.
U.S. Pat. No. 4,158,498 issued Jun. 19, 1979 and entitled “Blade cleaning system for a reproducing apparatus” discloses a reproducing apparatus that includes a blade cleaning system for removing residual material from an imaging surface. The blade is arranged for movement between a first position wherein an edge thereof engages the imaging surface to remove the residual material, and a second position wherein the edge is spaced from the imaging surface. Responsive to a movement of the blade to the second position a device is provided for removing residual material from the blade edge. A supply of lubricating agent is stored in a suitable container arranged above the device for cleaning the blade edge. A dispensing system is responsive to engagement between the blade and the blade edge cleaning device for dispensing a desired amount of lubricating agent onto the blade edge.
U.S. Pat. No. 5,463,455 issued Oct. 31, 1995 and entitled “Method and apparatus for adaptive cleaner blade lubrication” discloses an adaptive cleaner blade lubricating system for electrophotographic printing machines. In an electrophotographic printing machine, the amount of residual toner available to lubricate a cleaner blade is calculated based on the density of the transferred image. A band of toner is deposited in an inner document gap in selective widths so as to provide an adequate amount of toner to lubricate the cleaner blade across the full width of the photoreceptor. The lubricating band may be variable or may be a constant width with the frequency of placement of the band determined based on average image density for a group of documents. In the preferred embodiment, the width of the toner band is varied as a function of the overall residual toner in each pixel location across the width of the photoreceptor based on the density of the images transferred. As a result of the varying lubrication bands, the cleaner blade is maintained so as to not tuck and cause streaking and/or damage while toner efficiency is maximized.
U.S. Pat. No. 3,983,045 issued Sep. 28, 1976 discloses a developer composition comprising (1) electroscopic toner particles (2) a friction-reducing material of a hardness less than said toner and having greater friction-reducing characteristics than said toner material, and (3) a finely divided non-smearable abrasive material of a hardness greater than said friction-reducing and toner materials. An imaging and development process utilizing the above-identified composition including the step of maintaining the buildup of friction-reducing material on an imaging surface in the submicron range without completely removing or preventing said buildup, by the combined action of a cleaning force wiping at least any residual developed image from at least a portion of said imaging surface.
U.S. Pat. No. 5,463,456 issued Oct. 31, 1995 discloses a photosensitive drum unit for an electrophotographic apparatus, of the type of contacting a cleaning blade to the photosensitive drum in which a cleaning assistant composed of a lubricant capable of lowering the frictionally charged potential of the photosensitive drum caused by the friction of the photosensitive drum and the cleaning blade to not higher than 100 V is attached to the surface of the photosensitive drum, the cleaning blade or both.
U.S. Pat. No. 3,590,000 issued Jun. 29, 1971 discloses a toner with a lubricant additive described as a finely divided, rapid melting toner comprising a colorant, a solid, stable hydrophobic metal salt of fatty acid, a polymeric esterification product of dicarboxylic acid and a diol comprising diphenol.